I'd be interested to get your take on this concept of an electronic voting system:

1) Each voter enters the booth and a computer immediately generates a random number, let's call it a transient voter ID. The computer then prints out their number shuffled in with 10-20 other (real) transient voter IDs. User takes the printout and notes the position of their number.

2) Voter makes their selections, and their vote is recorded by the software.

3) At the end of the election, the ledger of all transient voter IDs and the accompanying vote is published.

Voters can confirm that their ID is present in the list, along with the correct candidate choice, and that the final totals were summed correctly. The general public can also spot-check that the appropriate number of votes per precinct are present. Yet since the printout includes 20+ other IDs, no one can prove conclusively who they voted for. The computer could ensure that at least one vote for each candidate is included on the printout.

There's really no need to trust the software since the vote ledger is fully published (also no need for blockchain).

They'd have to publish the ledger in real time and/or instantly show how those 10 to 20 voters voted, to the voter, for this to be effective. Otherwise whoever is paying or blackmailing that voter can ask the voter to mark their id and hand or transmit it to them immediately. They can later verify that the vote was given to the right choice once the ledger is published and take appropriate action for or against the voter. Voter cannot easily fake their choice, and in the case of blackmail, consequences for bad luck can be bad.

Edit: If you do show all 20 votes, you'd have to have votes for all candidates on them.

Also if someone is trying to manipulate a bunch of votes, they'd run into dupes and know one is lying.

Right, you would have to include a vote for each candidate in the set returned to the voter and generate the set in near realtime, at least for the first voters in each precinct.

Neither of those however should be difficult with electronic voting systems.

Seems like a verifiable, open voting ledger is a lot more transparent and obvious, regardless of the code and method of vote collection, which are orthogonal issues. No reason you couldn't use paper inputs and an ID into a public ledger. In fact, it should be much more consistent.

But a simple search on the internet shows that there are a lot of folks who don't want something like this.

Well, I'm the head of this family and this family supports the republicrats, so I'm going to be looking at your phone honey, to make sure you don't make a mistake.

Or, I'm offering $10 to you, junkie, to support my party. But if you want to be paid I'm going to use your device/private key/one time code to do it myself. Or maybe you're my employee and we'll have a voting party where I can see you all wisely agree with me.

The privacy of a voting booth where neutral officials who are supervised by all candidates doesn't allow either of these scenarios work.

couldn't they issue you a secure private key when you vote?

If you can verify your own vote, you can be forced to divulge that information. There's no technical solution to this problem.

There is a simple solution: generate a random public key as part of the voting process and print it out for later verification but also include plenty of other people's public keys in the printout.

The voter can remember the position of their own key if they choose to for later validation against the open ledger and can use the others for deniability (if needed).

That is not true. See work by Andrew Neff on verifiable shuffles of secrets. It is practical to produce a proof that can be verified by the voter but not useful in proving which way the ballot has been cast to anyone else.

I skimmed through the paper here (http://web.cs.elte.hu/~rfid/p116-neff.pdf) and it doesn't appear to solve the problem. Any time you can see your vote, so can anyone looking over your shoulder.

The described method seems to prevent voting authorities from seeing specific voter's votes, which is useful, but it doesn't solve the "show me you voted for X, or I break your legs" problem.

Yeah it makes the use of electronic voting less vulnerable to tampering, but obviously the voting still needs to he done in a private booth.

I don't feel like I could create trust in democracy with something as complicated as a private key for a mostly non-technical nation such as Canada or France.

I can simply demand your private key in exchange for a reward or avoidance of punishment. "Hand me your phone and I will cast this vote"

A more or less open voting ledger already exists without a blockchain. You can go to your Secretary of State and buy the record of voting in your state for somewhere between 0 and a few thousand dollars. You could also buy it from a private company which aggregates and resells that data. The only information not available is how particular individuals voted.